请帮忙分析一下句子结构

Question

.Were they salt domes such as are common along the United States Gulf Coast, and if so, why should there have been so much solid crystalline salt beneath the floor of the Mediterranean?
这句话Were they salt domes such as are common along the United States Gulf Coast是倒装句吗？那么正常语序是什么样子的？该如何翻译？

Answer 1

Were they.....虚拟倒装表示假设，and if so，强调，如果确实如此，
If they were salt domes such as (what) are common along the United States Gulf Coast, and if so, why should there have been so much solid crystalline salt beneath the floor of the Mediterranean?
如果它们确实是美国墨西哥湾地区常见的一种盐丘，那么为什么地中海大陆层下面会出现过那么多固体的晶盐